In an unusual move, the House Intelligence Committee today slapped former White House Chief Strategist Stephen Bannon with a subpoena when he refused to answer investigators’ questions during a closed-door meeting as part of their probe into Russian interference in the 2016 presidential election.

The lawmakers wanted Bannon to discuss, among other things, Trump’s firing of former FBI Director James Comey but he refused and claimed “executive privilege.”

It is unusual to issue a subpoena before an interview is even completed, and according to The Hill, it marks “a departure from how committee lawmakers have handled other witnesses who have declined to answer certain questions.”

More from The Hill:

“[Bannon] appeared to pique lawmakers when he tried to cite executive privilege to avoid answering questions related to his work for President Trump.”

Jack Langer, a spokesman for House Intelligence Committee chairman Devin Nunes R-Ca.) told the Associated Press that Bannon would not “discuss those topics” during a day-long interview on Capitol Hill.

Early today, a White House official told ABC News that the president did not ask for executive privilege concerning Bannon.

Later today, Rep. Adam Schiff (D-Ca.), the ranking Democrat on the committee, said this was the first time Republicans on the committee issued a subpoena after a witness refused to answer questions “at the instruction of the White House,” reports ABC News.

Schiff said the committee will now bring Bannon back for further questioning.

The subpoena was issued after it was ordered by Nunes, who is known to be a very close friend of Trump.

Nunes only recently rejoined the committee as chairman after the House Ethics Committee cleared him of charges related to his leaking information in the past to the White Hosue about committee findings before reporting them to his fellow committee members.

Bannon left the White House abruptly in August after losing an internal battle for power with Jared Kushner and others, ending his close relationship with Trump that began during the last stages of the 2016 campaign.

The relationship with the president really soured further last month with the publication of the book “Fire and Fury” by Michael Wolff, in which Wolff quotes Bannon making remarks that have angered and infuriated Trump.

Bannon in the book is quoted saying among other things that a June 2016 meeting at Trump Tower attended by Donald Trump Jr., Trump’s son-in-law Jared Kushner, who is also now a senior White House advisor, and others to get dirt on Secretary Hillary Clinton was “treasonous.”

Trump now refers to his former campaign manager and White House confidant as “Sloppy Steve.”

This was the second subpoena Bannon has received demanding he discuss these issues. The New York Times reported this morning that Bannon got a subpoena from Special Counsel Robert Mueller last week to testify before a grand jury in the ongoing federal investigation of the Russian and Trump campaign involvement in the 2016 election.

Bannon has gone in less than five months a top White House aide to being a top executive at the right-wing news site Breitbart – where he has now been forded out – to being completely unemployed.

Bannon has tried to apologize to Trump since the book came out, but the president by several accounts has frozen him out and has said he is no longer his friend.

How that might prompt Bannon to talk openly about Trump before Congress and the Grand Jury, now that Trump has disowned him, is an interesting question that could have huge implications for the investigations, and for Trump’s future as president.